While the concept of using wood as a primary vessel for beer making isn’t novel, it certainly isn’t in fashion these days.

Chris Schofield, brewer and part owner of Barreled Souls Brewing Co. in Saco, took some time with me to discuss his unique approach to brewing – using only wooden barrels to ferment his beers.

“It’s complicated, and there’s definitely more risk than working with stainless, but I believe it makes better beer and I managed to convince my partner and our employees, so here we are,” he said. Perhaps that’s why his brewery has undergone expansion and has gained a reputation for a lot of interesting beer choices of late.

The use of wood as a medium in brewing goes as far back as beer itself, but the role of the barrel has undergone a resurgence here in Maine. Intermingled with the vast stainless-steel vats and piping that one will see on nearly any beer tour, more and more barrels are being used as vessels to impart flavor, aroma, and mouthfeel to the beers coming out of the Pine Tree State.

Assistant cellarman at Barreled Souls Jesse Koelker and Justin McNelley showed me around the newly fashioned brewhouse in late August. After quaffing a few unique blends (aged over pistachio nuts, no less) they both expressed their love of barreled beers. “It’s the aroma and the flavor of what was in the barrels, and now the beer, that I love . . . people think a barrel-fermented IPA is strange, but we like it a lot,” said Koelker.

Barrel use for primary fermentation, or secondary conditioning, can enhance many aspects of beer or lend itself to risks with contamination. Schofield went on to remark that “the challenges have mostly had to do with essentially inventing the process. Not inventing barrel fermentation itself . . . but inventing, for Barreled Souls at least, processes, methods, equipment, and a production facility to make it all work. There’s been a lot of trial and error, but as of today, four years and almost 1,000 batches in, we’ve got it fairly figured out.”

The influence of wood can change the flavor of a beer drastically. Each has its own characteristics that can even alter the fermentation occurring in a barrel. The type of wood, where it came from in the world, what it was used for prior to holding beer, and the barrel’s maintenance history, are all considerations in the process.

For example, if the barrel was originally used for a distilled spirit, then initial beer introduction can have a very powerful flavor of the original spirit. If there is char inside the barrel, it can act as an agent to help clarify the beer through a small amount of filtration, as well as mellow a beer’s sharp bite, while impacting a rich, earthier note. Some barrels that housed wines will react differently and can grant fruitier tangs or even spice notes like vanilla and cinnamon.

The environment within a barrel can also be exceedingly complex. In fact, many of the barrels for farmhouse and wild style ales can create a sustained biome within the wood itself, allowing spontaneous fermentation for many years. Often this is used in many unique Belgian styles like lambic and geuze and the bacterial cultures in the barrels often impart a terroir that can be unique to a brewery. Cellarmen are often employed to help care for, and to assist with, blending of many barrels, since creating a uniform flavor year after year is a uniquely challenging task. It is not uncommon for some sour beers to be aged for years in oak casks or barrels before being blending and bottled for consumption.

And finally, there is one other factor that brewers with traditional systems don’t have to worry about: the cleanliness of the barrel itself. While stainless-steel can be scrubbed, chemically scoured, boiled, and otherwise sterilized to make consistent product over and over, if a barrel breaks down or becomes contaminated, it is no longer useful and often repurposed into a kitschy Adirondack chair or bar stool. Brewers must be vigilant in how they maintain their assets, or they stand to lose potentially expensive product to carelessness or just being unlucky. “I’ve had to dump entire barrels of our Stay Puft,” remarked McNelley, “but when something bad gets into the barrel, you can’t get it out.”

Provided it was maintained correctly, barrel aging and fermenting beer can change the entire product you drink from something commonplace to something uniquely inspired. As you select your next craft brew this fall, try something touched by a barrel’s influence and see how it strikes you. You may find yourself pleasantly surprised.

— Text: Matthew Brown. Matt is a Certified Beer Server, a member of the American Homebrewers Association, and recently studied brewing in Belgium. He lives and works in Portland.